The present invention relates to turbine engines. In particular, the invention relates to cooling channel pedestal arrays for a turbine engine.
A turbine engine employs a series of turbine stages to extract energy from a flow of combustion gases to perform useful work. Turbine stages include airfoils, for example, stator vanes and rotor blades; and shroud components to contain the flow of combustion gases, for example, blade outer air seals, rotor blade platforms, and stator vane platforms. These turbine stage components are directly exposed to the flow of combustion gases and must survive in a high-temperature environment. Often, portions of airfoils or shrouds exposed to high temperatures are hollow, having internal cooling channels that direct a flow of cooling air through the airfoil or shroud to remove heat and prolong the useful life of the component.
A source of cooling air is typically taken from a flow of compressed air produced upstream of the turbine stages. Some of the energy extracted from the flow of combustion gases must be used to provide the compressed air, thus reducing the energy available to do useful work and reducing an overall efficiency of the turbine engine.
Internal cooling channels are designed to provide efficient transfer of heat between the component to be cooled and the flow of cooling air within. As heat transfer efficiency improves, less cooling air is necessary to adequately cool the component. Internal cooling channels typically include structures to improve heat transfer efficiency including, for example, pedestals (also known as pin fins). Pedestals may link opposing sides of the internal cooling channel and improve heat transfer by increasing both the area for heat transfer and the turbulence of the cooling air flow.
While the use of pedestals in internal cooling channels improves heat transfer efficiency between turbine engine components exposed to a flow of combustion gases, further improvement in the heat transfer efficiency of pedestal arrays can improve overall turbine engine efficiency.